MXPA97007280A - A processing to process the residuals of desecination - Google Patents

Abstract

In a processing to process residues from the incineration of waste, such as, for example, slag from the incineration of waste, in which the slag is subjected to a reduction process while metals are separated, in which waste from the Waste incineration is introduced into a slag bath of steel plant, in quantities ranging from 15 to 45% by weight, based on the average amount, that heavy metals or heavy metal compounds, such as Zn chloride, Pb , Cd or Hg, which are evaporated during the function of residues from the incineration of waste or slag is removed and the liquid bath is reduced with the help of carbon carriers and under the formation of an iron bath, after which The spent slag phase of the metals is granulated and used as a mixed cement component

Description

A procedure for processing residues from waste incineration The invention relates to a process for processing residues from the incineration of waste, such as, for example, slag from waste incineration, in which slag is subjected to waste. A reduction procedure while separating metals. In relation to the procedures for domestic and industrial waste disposal, it has already been proposed to reduce the slag phases, in the liquid state that are formed during combustion due to the oxidation conditions involved, in order to recover the metals and / or the alloys. However, these parts of the plants arranged to follow a waste incineration plant, as a rule, are relatively complex and, in particular, with incineration plants of small waste that are not easily operated, in an economical way. This must be taken into account since slag from waste incineration can contain relatively high portions of heavy metals and non-ferrous weigher metals, so that the discharge of these slag from waste incineration is not easily feasible. In addition, the processing of slag from the incineration of waste, liquids presupposes an adequate volume of slag, which requires additional heat, and therefore, additional energy, due to the unfavorable viscosity of the slag, which are formed during the incineration of waste. The invention proposes a processing of residues from the incineration of waste, such as, for example, slag from waste incineration, of different origins, in a form that is safe for the environment and that directly produces products, characterized by low contents of materials harmful and that are used as raw materials, for later use in the acreage plants. At the same time, the invention is directed towards the production, from waste incineration slag with initially unfavorable properties, of synthetic blast furnace slag having good hydraulic properties. In order to solve this problem, the method according to the invention consists, essentially, in that residues from the incineration of solid waste are introduced in a slag bath of a steel plant, in quantities varying from 15 to 45% by weight, based on the total amount, that heavy metals or heavy metal compounds, such as Zn, Pb, Cd or Hg chlorides, which evaporate during the melting of waste incineration residues or slag are removed and the bath Liquid is reduced by the help of carbon carriers and under the formation of an iron bath, after which the spent slag phase of the metals is granulated and used as a mixed cement component. Because waste from the incineration of solid waste is used, residues from the incineration of waste from different sources can be collected and used, and by the fact that these residues from waste incineration are introduced into a bathroom of slag from steel works, the mixed slag is adjusted having a corresponding basicity with that high quality blast furnace slag. By adjusting the basicity in typical values of the blast furnace slag with high quality, which is achieved by adding residues from the incineration of waste to a slag of strongly basic steel works, the viscosity is substantially reduced and the desirable metallurgical treatment is It can be carried out at comparatively low temperatures. The neutralization of the heat emitted by mixing the slag from strongly basic steel works with residues from the incineration of acid waste at the same time, allows the fusion of waste from the incineration of waste in a form as widely autothermal as possible, in a way that you do not have to supply any or almost no additional energy while, simultaneously the viscosity is decreased. Therefore, by using a steel plant bath in the liquid phase it is possible to carry out, simultaneously with the decrease of the iron oxide content of the slag when iron is separated, a common or fractional separation of the metal phases while The liquid slag bath is reduced with carbon carriers under the formation of an iron bath. In this way, the iron bath that has the quality of the raw iron is obtained immediately, at the same time, the composition of the slag of original steel works is adjusted to a composition of high quality blast furnace slag with, in the due form, the substantial improvement of hydraulic properties. In the course of the reduction process, relatively high portions of heavy metals can be safely separated and in addition the remnant of the crude iron can be used directly in the steel plant. In its entirety, the process according to the invention can be carried out following a steel work procedure and by means of the devices that are available directly in the steel plant in such a way that the expenses in additional apparatuses for the desired purification can be obviated and the elimination of residues from waste incineration. As a whole, existing devices can be used without the need for singular adaptation work and the desired composition of the blast furnace slag can be chosen by selecting and mixing the waste incineration waste used at the same time. time it is feasible to treat relatively high amounts of waste from the incineration of solid waste.

Advantageously, the process according to the invention can be performed in a manner that the temperature of slag bath liquids is maintained by blowing oxygen or air into the carburized Fe bath during the reduction. From the slag bath of steel works, which contains high portions of iron oxide, an iron bath is separated during the reduction, whose iron bath will settle more easily due to its reduced viscosity after the addition of the residues of the iron. incineration of acid waste. In its entirety, the residual amount of the iron bath can be loaded already at the beginning of the process, which can be performed within the scope of a steel work procedures in the same way, where the carbon is introduced into an iron bath with the purpose of reducing, and therefore, causing the iron bath to carburize. In order to limit the carbon content of the iron bath to common values for crude iron, the excessive amount of carburization occurs in the course of slag bath reduction due to the equilibrium reactions that take place between the Slag and bath can be used to maintain the temperature of the liquids by blowing oxygen or air and, therefore, gasify the carbon into carbon monoxide. This carbon monoxide that is formed in this way causes a reduction of the iron oxide of the slag, as well as, optionally of the heavy metals dissolved in the slag, which are usually in the oxidic form, such as copper, tin, nickel and chrome. In this way, the carbon monoxide that is advantageously formed at least partially can be fed to be used as energy inside the converter, where it is advantageously processed so that waste from the incineration of the waste is introduced into the slag of the steel works inside a converter, particularly one of blow at the bottom, equipped with nozzles for 02 or air, of course, which is used, in operation with, for example, electric furnaces with an integrated burner or other converters of reduction that are conceived. Still, the use of a lower blow OBM converter is a particularly preferred variant both in terms of the apparatus and in terms of the use of energy. In order to achieve the desired viscosity of the slag, it is an advantage to proceed so that from 20 to 40% by weight of the residues from the incineration of solid waste is introduced in 60 to 80% by weight of steel works or LD slag.

As mentioned at the beginning, the crude iron formed by the reduction, in a particularly advantageous manner, can be used as slag in a steel plant. It is advantageous to ensure that slag is particularly beneficial and control of the iron bath, especially with high portions of non-ferrous metals, in such a way that the reduction of the liquid slag phase takes place in at least two steps, where, in a first phase, the Feo content of the slag phase is maintained between 1.5 and 5% by weight, preferably above 2% by weight, and the FeO bath is discharged and, subsequently the slag is reduced to Fe-M, Fe-Cr and Fe-V alloys after adding carbon-free reducing agents, such as Al, Fe-Si. By the fact that the FeO content of the slag is maintained above 1.5% by weight and advantageously, above 2% by weight, Cr, V, and Mn remain in the slag and separation, in a selective manner , it is viable after the separation of the Fe bath in a second reduction in an enriched manner. When residues of waste incineration are introduced, in solid form in the slag bath of the steel works, the heavy metal chlorides and optionally the oxides will evaporate first. In particular, zinc, lead, cadmium and mercury practically quantitatively. Similarly, the copper, tin and nickel chloride compounds are able to partially evaporate by the time waste from waste incineration is introduced. Precisely, it subtracts the chromium in the slag practically quantitatively, optionally, also a large portion of sulfur present is incorporated into the slag. The oxidized heavy metals dissolved in the slag and, in particular, in the iron oxide of the slag, such as copper, tin, nickel and chromium, by carbon or carbon monoxide dissolved in the iron bath, can be Easily and quickly reduce iron in its regular form. If the chromium remains in the slag, it can be reduced quickly and easily in the iron bath by adding aluminum or iron silice or any other carbon-free reducing agent. In its entirety, a reduced, largely purified slag of non-ferrous metals thus formed can be used as an optimum mixed cement component or synthetic blast furnace cement. The final product is characterized by an extremely low content of heavy metals, the crude iron that is formed and which has a comparatively high portion of carbon is reused, directly, in liquid form in a steel plant.In the following, the invention will be explained in more detail by the exemplary embodiment. LD slag has the following composition Steel 20% by weight Si02 13% by weight A1203 1% by weight CaO 33% by weight MgO 4% by weight FeO 21% by weight S 0.05% by weight P 0.5% by weight Cr 0.15 % by weight is introduced into the blow converter below an average of 70:30 with the slag from the waste incineration that the composition has: Si02 43% by weight CaO 13% by weight A1203 8.5% by weight Fe203 10% by weight MgO 1.5% by weight Na20 3.5% by weight S03 1% by weight Ti02 1.5% by weight Cu 0.4% by weight Ni 0.04% by weight Cr 0.15% by weight Zn 0.35% by weight Pb 0.15% by weight the mixture is made intense Mixed slag is characterized by having the following composition Steel 17% by weight Si02 24% by weight CaO 28% by weight A1203 6% by weight Fe203 18% by weight MgO 3% by weight Na20 1% by weight S03 0.3% by weight Ti02 0.6% by weight Cu 0.15% by weight Ni 0.02% by weight Cr 0.2% by weight P 0.35% by weight After reduction of the slag that has been effected, a synthetic blast furnace slag having the following composition S? 02 38% by weight CaO 43% by weight A1203 11% by weight MgO 5% by weight Na20 2% by weight formed, the reduction is carried out in an OBM converter with the help of carbon, carbon monoxide and aluminum. No more heavy metals were detected when using X-ray fluorescence analysis, in the pure slag obtained in this way, from which it can be concluded, clearly, that these metals can only be present below the 100 ppm. The water-granulated slag corresponds to the highest quality hydraulically baked blast furnace slag in the mixed cement, excelling for an Index according to Keil, greater than 100%. Crude iron formed is recovered with the following composition C 3.5% by weight Cu 0.5% by weight Ni 0.1% by weight Cr 0.6% by weight P 1% by weight Al 1.5% by weight Fe balance Crude iron excels by a content With relatively low heavy metal content and, in particular, low copper content, this iron is processed in a steel plant advantageously.

Claims (1)

Claims 1. A process for processing residues from the incineration of waste, such that, for example, slag from waste incineration, in which the slag is subjected to a reduction process while the metals are separated, which is characterized in waste from waste incineration is introduced into a slag bath of the steel plant, in quantities ranging from 15 to 45% by weight, based on the average amount, than heavy metals or heavy metal compounds, such as Zn, Pb, Cd or Hg chloride, which evaporate during the melting of waste from the incineration of waste or slag is removed and the liquid bath is reduced with the help of carbon carriers and under the formation of an iron bath , after which the spent slag phase of the metals is granulated and used as a mixed cement component. 2. The process according to claim 1, characterized in that the temperature of the slag bath liquids is maintained by the blowing of oxygen or air in the carburized Fe bath during the reduction. 3. The process according to claim 1 or 2, characterized in that 20 to 40% by weight of the residues from the incineration of solid waste is introduced in 60 to 80% by weight of slag of steel works or LD . 4. The method according to claim 1, 2 or 3, characterized in that waste from waste incineration is introduced into a converter, particularly a lower blower, equipped with 02 or air nozzles. 5. The process according to any of claims 1 to 4, characterized in that the crude iron that is formed by the reduction is used as slag in a steel plant. 6. The process according to any of claims 1 to 5, characterized in that the reduction of the liquid slag phase is carried out in at least two steps, wherein in the first phase the Urea content of the slag phase is maintained between

1.5 and 5% by weight, preferably above 2% by weight, and the Fe bath is discharged and subsequently the slag is reduced to alloys of Fe-Mn, Fe-Cr and Fe- V after the addition of carbon-free reducing agents, such as, for example, Al, Fe-Si.